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| author | Josh Stone <jistone@redhat.com> | 2020-08-09 12:41:09 -0700 |
|---|---|---|
| committer | Josh Stone <jistone@redhat.com> | 2020-08-09 12:41:09 -0700 |
| commit | ca0b89aa040acf5df95d39579cbd7ff03c73baf1 (patch) | |
| tree | 79c58ef22f3171ae1ed9e7142167a361c6cfa9e1 | |
| parent | 1d03ffe0bce458f68f279cd240dd15f20d39449b (diff) | |
| download | rust-ca0b89aa040acf5df95d39579cbd7ff03c73baf1.tar.gz rust-ca0b89aa040acf5df95d39579cbd7ff03c73baf1.zip | |
rustc_span: note the perf loss seen from IndexSet in symbol::Interner
| -rw-r--r-- | src/librustc_span/symbol.rs | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/librustc_span/symbol.rs b/src/librustc_span/symbol.rs index 5203bfdb3b7..ca9702784a2 100644 --- a/src/librustc_span/symbol.rs +++ b/src/librustc_span/symbol.rs @@ -1481,6 +1481,10 @@ impl<CTX> ToStableHashKey<CTX> for Symbol { } // The `&'static str`s in this type actually point into the arena. +// +// The `FxHashMap`+`Vec` pair could be replaced by `FxIndexSet`, but #75278 +// found that to regress performance up to 2% in some cases. This might be +// revisited after further improvements to `indexmap`. #[derive(Default)] pub struct Interner { arena: DroplessArena, |